Should Oracle database sessions be killed at OS level or within the database?

Question

Should Oracle database sessions be killed at operating system level or within the database?

Answer

Do not kill Oracle database sessions at the operating system level by killing the corresponding database server process.

Instead, use the following SQL statement:

ALTER SYSTEM KILL SESSION '<sid>,<serial#>';


This statement acts in the following manner:

(1)
It terminates a session, rolls back ongoing transactions, releases all session locks, frees all session resources.

(2)
If the session is performing some activity that must be completed (e.g. waiting for a reply from a remote database or rolling back a transaction), Oracle waits for this activity to complete, kills the session, then returns control.

(3)
If the wait lasts for 60 seconds then Oracle marks the session to be killed, and returns control with a message that the session is marked to be killed. The session then gets killed when the activity is complete.

For detailed instructions on how to kill an Oracle database session in a clean way, please see KCS Article 000022533 "How to kill an Oracle database session".

Additional Information

Source: My Oracle Support Note 161794.1 "Should Sessions be Killed in OS or Using Alter System Kill Session?"

Category: Installation & Upgrades (500) - ALEPH

Subject: Installation - ALEPH

• Article last edited: 3/18/2014